1. Field of Invention
The present invention relates to a magnetic data processing apparatus such as a check reading apparatus having a magnetic head and a motor, and relates more particularly to an improvement for reducing noise produced in the magnetic head in response to leakage flux from the motor.
2. Description of Related Art
A check reading apparatus conveys a check on which magnetic ink characters are printed through the transportation path on which a magnetic head is disposed to read the magnetic ink character information. A stepping motor or other type of electric motor is used as the drive source of the transportation mechanism for conveying the check. Such motors produce leakage flux which can cause the magnetic head to produce noise represented by electromotive forces. Noise produced by the magnetic head will interfere with its reading the information in the magnetic ink characters on the check. It is therefore necessary to suppress the noise caused by leakage flux from the motor.
Japanese Unexamined Patent Appl. Pub. JP-A-H11-306502 teaches a mechanism for suppressing this noise. The mechanism taught in JP-A-H11-306502 covers the motor with a shield plate to control the direction of leakage flux from the motor, and positions the motor and the magnetic head relative to each other so that the flux is oriented in a direction that does not produce electromotive force (noise) in the coil of the magnetic head. This suppresses noise applied to the magnetic head due to leakage flux from the motor.